page_title: Modular connector
section_title: Pinout
hierarchical_section_title: Modular connector / 8P8C / Pinout
caption_attribution_description: Italiano: Schema connettore RJ-45 - Cablaggio EIA/TIA-568A - Orientamento sx - Elaborazione personale
context_page_description: A modular connector is a type of electrical connector for cords and cables of electronic devices and appliances, such in computer networking, telecommunication equipment, and audio headsets.
  Modular connectors were originally developed for use on specific Bell System telephone sets in the 1960s, and similar types found use for simple interconnection of customer-provided telephone subscriber premises equipment to the telephone network. The Federal Communications Commission mandated in 1976 an interface registration system, in which they became known as registered jacks. The convenience of prior existence for designers and ease of use led to a proliferation of modular connectors for many other applications. Many applications that originally used a bulkier, more expensive connector have converted to modular connectors. Probably the best known applications of modular connectors are for telephone and Ethernet.
  Accordingly, various electronic interface specifications exist for applications using modular connectors, which prescribe physical characteristics and assign electrical signals to their contacts.
context_section_description: 8P8C connectors are frequently terminated using the T568A or T568B assignments that are defined in TIA/EIA-568. The drawings to the right show that the copper connections and pairing are the same, the only difference is that the orange and green pairs (colors) are swapped.  A cable wired as T568A at one end and wired as T568B at the other end (Tx and Rx pairs reversed) is an Ethernet crossover cable. Before the widespread acceptance of auto MDI-X capabilities, a crossover cable was needed to interconnect similar network equipment (such as Ethernet hubs to Ethernet hubs). A cable wired the same at both ends is called a "patch" or "straight-through" cable, because no pin/pair assignments are swapped. Crossover cables are sometimes still used to connect two computers together without a switch or hub, however most network interface cards (NIC) in use today implement auto MDI-X to automatically configure themselves based on the type of cable plugged into them. If a "patch" or "straight" cable is used to connect two computers with auto MDI-X capable NICs, one NIC will configure itself to swap the functions of its Tx and Rx wire pairs.
caption: T568A wiring.
exif: {}